Incontinence is a complex disorder with often more than one cause, a factor that has complicated the search for effective solutions. The five major categories of incontinence include: overflow, urge, stress, mixed (combination of both urge and stress), and functional. Male incontinence makes up approximately 15% (1.4 million) of the urinary incontinence population (male and female) with the majority experiencing mixed incontinence, followed by urge or stress incontinence. Stress urinary incontinence is a well-known complication of radical prostatectomy and transurethral resection of the prostate (TURP).
Several large studies have examined the median probability for developing stress urinary incontinence following all forms of surgery for benign prostatic hyperplasia (BPH). The European Association of Urology (EAU) and the American Urological Association (AUA), as well as the National Health and Medical Research Council (NHMRC) of Australia have all conducted extensive literature searches and reviews, examining the outcomes of surgeries for BPH. Incontinence rates reported by these three reviews following transurethral incision of the prostate (TUIP) range between 0.1%-0.75%, and following TURP between 1%-2.2%. Open prostatectomy produces between 0.5%-1.9% incontinent patients. The NHMRC summary reported total incontinence and stress incontinence separately, with the incidence of 1% (90% CI 0.7-14%) and 2.1% (90% CI 1.75-2.5%) respectively found in the literature. Of the three operations, TURP is the most widely and commonly employed procedure. Approximately 195,000 TURPs are performed annually in the USA.
Benoit et al. (Urol., 56:116 (2000)) examined the records of 25,651 men who were reported under Medicare statistics in 1991 as having undergone a radical retropubic prostatectomy (RRP) for cancer of the prostate. Nearly 22% (5573 of 25,651 men) reported incontinence post RRP and at 12 months post-RRP, 8% (2025 men) continued to carry this diagnosis.
The largest study to date to assess the frequency of diagnosis of prostate carcinoma and post prostatectomy incontinence is Mifflin et al. (Cancer, 83:1679 (1995)). Data from 1,114 hospitals and 103,979 subjects diagnosed with prostate cancer in 1992 were surveyed. The survey team defined regular urinary incontinence as an unwanted loss of urine at least twice over the past month. The results demonstrated the overall rate of incontinence to be up to 20-22% in the community dwelling patients and that the surgical mortality rates from the surgery were approximately one percent.
The majority of men with incontinence associated with various forms of prostatectomy are conservatively managed using absorbent products (pads/adult diapers) or occlusive products (penile clamps) while the patient “watches and waits” to see whether improvement will occur with the passage of time. Most reports on post-prostatectomy incontinence and its treatment agree that a follow-up period of at least 12 months is necessary before confirming an individual's status as one of established incontinence.
Stress urinary incontinence has a high probability of natural resolution within the first year post-surgery (Mebust, Chapter 49 in Campbell's Urology, p. 1511 (1998)). During this period several therapies, such as pelvic floor training, medication, and bulking agents, may be helpful in restoring continence sooner, but differences compared with no treatment typically disappear by 12 months post-procedure. Stress incontinence lasting longer than 12 months, and/or not responding to conservative treatment may be improved using surgically implanted devices. Devices include the Artificial Urethral Sphincter (AUS) and sub-urethral slings.
The AUS is currently considered the gold standard for treatment for chronic stress urinary incontinence especially severe cases. The implantation of device qualifies as a major procedure with required surgical placement of several components including the circumferential urethral cuff, the pressure-regulating balloon, and the scrotal pump which controls inflation and deflation of the urethral cuff for continence. This cuff mechanism eliminates passage of urine; the recipient manipulates the device to open the urethra. Manipulation requires some manual dexterity. Revisions of the AUS typically involve surgical risks consistent with the original procedure. With AUS, the reoperation rate is found to be 22-25% but the reoperation rate is both complicated and invasive.
Sub-urethral slings represent a variety of devices based on passive, semi-circumferential urethral compression. Devices differ in material and in how and/or where they are anchored. Most are fixed, like the AUS, but a few feature adjustable tension, e.g. Remeex System (K062341). Published literature reviews (Mebust, supra, and Borgermann et al., 107:454 (2010)) suggest improvement rates (less stringent than social continence) of 75% to 90% with easier implantation and fewer adverse events and revisions than the AUS in mild to moderate cases. The most common adverse events reported were infection, 0% to 6%, urethral erosion, 0% to 2% and post implant scrotum pain or numbness resolving within three months, 16% to 72%. Urethral slings are cheaper and less invasive and show dry rates of 42-70% (Rocha et al., Urol., 71:85 (2005)). Slings however, carry a considerable risk of urinary retention and pain (Herschorn et al., Neural. Urodvn. 29:179 (2010)). Less invasive treatments, such as the injection of a bulking agent (Macrroplastique) in the external sphincter, have also been tried but the long-term results are poor: only 25% of the patients have any treatment effect on pad use after 12 months (Stein et al., J. Urol., 173:1654 (2005)).